My best suggestion is to get the unit serviced. It may be a power supply or board issue, but without looking at it, it's difficult to diagnose.
Good evening, I have a LNT4061F that has just started havung problems. I can't turn it off unless i unplug it from the outlet, there is no picture with the exception of agreen line at the top and then through the middle. When I plug the unit back in the power indicator flashes 3 times pauses and begins flashing again. I have disconnected all inputs to no avail. I have seen some other threads that relate to this problem somewhat but not exactly. Any help or advice would be greatly appreciated.